What it is
A blockchain is a type of distributed ledger that organizes data into blocks, which are then linked together using cryptography. Each block contains a timestamp and transaction data, and once validated and added to the chain, it becomes extremely difficult to alter. This structure creates an immutable and transparent record of all network activity. The network is maintained by multiple participants (nodes) that collectively validate and store copies of the ledger, removing the need for a central authority.
Blockchains form the foundation of most cryptocurrencies and decentralized applications. News frequently reports on new blockchain projects, upgrades, or applications being built on existing chains like Ethereum. The security, transaction speed, and cost of a blockchain are key factors influencing its adoption and the value of its native cryptocurrency. Retail investors should understand that the blockchain's integrity underpins the security and functionality of their digital assets and decentralized interactions.
Why it matters
Blockchain is the core technology behind crypto assets and DeFi. Grasping its immutable, decentralized nature is fundamental to understanding the entire ecosystem.
Reviewed under editorial standardsUpdated September 26, 2026Not investment advice